This invention relates to organic polymers having high water wettability, molded or otherwise formed products comprising the organic polymers, novel polymerizable compounds and compositions capable of affording organic polymers having high water wettability, and antifouling materials, anti-mist materials, dew preventing materials, water (liquid) absorbent materials and optical materials, all of which make use of organic polymers and molded or otherwise formed products having high water wettability.
As a representative physical value expressing water wettability, water contact angle is known. In general, those having water contact angles of less than 90xc2x0 are classified as hydrophilic materials, and those having water contact angles of greater than 90xc2x0 are classified as water repellant materials. As the water contact angle approaches from 90xc2x0 toward 0xc2x0, the material can be considered to be higher in water wettability.
High water wettability is extremely effective for water retaining materials or the like, which are useful, for example, for the inhibition of dew-induced misting of windowpanes, mirrors, agricultural vinyl sheets, eyeglass lenses, camera lenses and the like, for the suppression of a reduction in the efficiency of heat exchange due to formation of water droplets and deposition of fouling substances on cooling fins, for the protection of building exterior walls and the like from fouling by improving their property to eliminate (self-clean), with rain or water, fouling (airborne hydrophobic substances) deposited on the building exterior walls, for the improvement of dew preventing property of building interior finish paints and materials and the like, for the improvement of contact lens wear comfort and anti-fouling property, and for water-retention materials used for the greening of deserts or the growth promotion of general plants.
In these applications, the products are large in size or complex in structure, accuracy is required, productivity, controllability and product flexibility and safety are needed, water absorbency is needed, and coloration or dyeing is preferred. Accordingly, difficulties are encountered with inorganic materials in any instances, resulting in an increasingly high demand for organic materials.
Known as organic materials capable of showing high water wettability include polymers such as polyvinyl alcohol [water contact angle: 36xc2x0, xe2x80x9cCho-shinsui Cho-hassuika Gijutsu (Superhydrophilicity, Super Water-repellancy Imparting Technology)xe2x80x9d, Published by Gijutsu Joho Kyokai Co., Ltd., 2001], polyisopropylacrylamide (water contact angle: about 44xc2x0 Langmuir, 11, 2301, 1995), and polyacrylonitrile (water contact angle: about 53xc2x0, Desalination, 72, 263, 1989).
These polymers show the effect by hydroxyl groups, nitrile groups or amide groups which they themselves have. These functional groups are, however, known to be high in reactivity, and in some instances, may tend to cause a quality deterioration or change in final products due to induction of undesired unnecessary reactions such as acetylation with aldehydes, esterification with acids or acid anhydrides, changes into amides or carboxylic acids through hydrolysis and esterification by alcoholysis or the like, and induction of Diels-Alder reaction or Michael addition [xe2x80x9cPlastic Jiten (Plastic Dictionary)xe2x80x9d, Published by Asakura-Shoten Pub., Co., Ltd., 1992]. Such polymers are accompanied by further problems such that they themselves may be dissolved or eluted into water and may be low in mechanical strength or the like.
With a view to solving, for example, problems of dissolution or elution, mechanical strength and the like, it has been proposed to add copolymerizable compounds to form them into network polymers. This modification, however, has a tendency of deteriorating the wettability, and is not considered to be a proposal that assures sufficient strength while retaining high wettability.
As an unconventional material, an agar gel (water contact angle: about 20xc2x0, Langmuir, 10, 2435, 1994) is known. It is, however, not considered to be sufficient in physical and chemical properties for its insufficient mechanical strength, insufficient heat resistance and insufficient water resistance and chemical resistance. Practically, it is extremely difficult to use it for such purposes as described above.
As other methods for exhibiting high water wettability, methods which primarily involve surface modifications are known, including a method that provides a photocatalytic reaction layer of titanium oxide (JP 11-58629 A, JP 11-1659 A), a method that coats a coating formulation making use of silanol groups (JP 9-40907 A, JP 9-40908 A, JP 11-21826 A), a method that subsequent to corona discharge treatment, provides a layer containing silyl groups and ionic hydrophilic groups (carboxyl groups) and polyvinyl alcohol (JP 9-76428 A), a method that provides a layer making use of a quaternary ammonium base (JP 10-296895 A), a method that forms a number of micropits on a surface by etching treatment (JP 7-198290 A), a method that introduces active hydrogen groups such as an amido group, carboxyl group and hydroxyl group, or ionic functional groups such as sodium sulfonate, into a surface by graft copolymerization (J. Poly. Sci., Part A: Polym. Chem., 32, 1569, 1994; Macromolecules, 25, 6842, 1992), and a method that treats a surface with a chloric acid-potassium chlorate mixed solution [Polymer (Korea), 24, 877, 2000].
According to these methods, high water wettability can be certainly realized in some instances. However, they tend to cause various problems such as decomposition at the interface with a coated material through a photocatalytic reaction, ineffectiveness in a dark ambient, delamination due to differences in a physical property such as coefficient of linear expansion, flexibility or refractive index, crazing in a coating layer or a coated material, development of interference bands, insufficient strength and weather resistance of a coating layer and a treated surface, and a reduction in performance due to an undesired reaction with active hydrogen groups or ionic groups. On top of these problems, these methods generally require high ingenuity and special apparatus in many instances, and also require a procedure of forming molded or otherwise formed products beforehand and then treating or coating the products further. These surface-modifying methods, therefore, are proposals that lead to cumbersome production and are not considered to be effective, tend to result in high cost, and in some instances, also have some doubts in safety.
In the field of resins, polymers and the like, on the other hand, the possession of excellent transparency is significantly effective. They can be used in the field of optical materials led by spectacle lenses, contact lenses, camera lenses, pickup lenses and organic glasses and the field of transparent materials such as transparent films, and moreover, are expected to develop new markets and high functionality, such as improvements in color vividness and luster, in the field of paints, coating formulations and the like.
Nonetheless, it has been unknown whether or not high-wettability organic polymers with which the present invention are concerned have high transparency.
Namely, it has been extremely difficult to solve the above-mentioned numerous problems and to propose organic polymers, resins and the like having high wettability and high transparency.
With such circumstances in view, the present inventors have proceeded with an extensive investigation. As a result, it has been found that use of a polymerizable compound having a polar structure, the dipolar moment of which is high (about 3 debyes or higher), as a partial structure is effective for solving the problems and also that among such polar structures, an alkylene(thio)urea structure analogous to the structure of polyurea considered to be poor in practical utility for its high cost and low thermal stability [xe2x80x9cPlastic Daijiten (Encyclopedia of Plastics)xe2x80x9d, Published by Kogyo Chosakai Publishing Co., Ltd.] is more effective. The present inventors have also found polymerizable compounds having a novel alkylene(thio)urea structure which can bring about more preferred results.
The present inventors have also found that the wettability of a polymer is drastically improved by copolymerizing a polymerizable compound having the above-described polar structure.
According to the above method, organic polymers which are physically and chemically stable despite their high water wettability and are excellent in transparency can be efficiently obtained without needing special ingenuity and apparatus and a cumbersome procedure such as conversion. organic polymers according to the present invention can be suitably used for applications in antifouling materials (self-cleaning materials), anti-mist materials, dew preventing materials, water (liquid) absorbent materials, optical materials and the like. Described specifically, the present invention relates to:
[3] An organic polymer as defined in [1] or [2], which has a polar structure of 3 debyes or higher in dipole moment.
[4] A molded or otherwise formed product comprising an organic polymer as defined in [1], [2] or [3].
[5] A polymerizable compound comprising, in a molecule thereof, one or more of the following partial structural formula (A): 
wherein A1 to A6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X1 represents O or S, and 1 stands for an integer of 0 to 2, and one or more thioepoxy groups, allylthio-carbonyl groups or allyloxycarbonyl groups.
[6] A polymerizable compound comprising, in a molecule thereof, one or more of the following partial structural formula (A): 
wherein A1 to A6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X1 represents O or S, and l stands for an integer of 0 to 2, and two or more mercapto groups, glycidylthio groups or (meth)acryloylthio groups.
[7] A polymerizable compound represented by the following formula (B): 
wherein A1 to A6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X1 represents O or S, 1 stands for an integer of 0 to 2, R1 to R4 each independently represent a hydrogen atom, a hydroxy group, a mercapto group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or the below-described formulas (C) to (F), m and n each independently stand for an integer of from 0 to 10, M and N each independently stand for an integer of from 1 to 10, R5 and R6 each independently represent an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or the below-described formulas (C) to (F), with a proviso that any one or more of R1 to R4 are any of the below-described formulas (C) to (E): 
wherein A7 represents a hydrogen atom or a methyl group, and X2 represents O or S; 
wherein A8 represents a hydrogen atom or a methyl group, and X3 and X4 each independently represent O or S; and 
wherein A1 to A6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X1 or X5 represents O or S, l stands for an integer of 0 to 2, R7 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms or an alkylthioalkyl group having 2 to 12 carbon atoms, R8 and R9 each independently represent a hydrogen atom, a hydroxy group, a mercapto group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an alkylthio group having 1 to 6 carbon atoms, q stands for an integer of from 1 to 6, and r stands for an integer of an integer of from 0 to 3.
[8] A polymerizable composition comprising a polymerizable compound as defined in [5], [6] or [7].
[9] An organic polymer available from polymerization of a polymerizable compound as defined in [5], [6] or [7] or a polymerizable composition as defined [8] and having a water contact angle of 20xc2x0 or smaller.
[10] An organic polymer available from polymerization of a polymerizable compound as defined in [5], [6] or [7] or a polymerizable composition as defined in [8] and having a water contact angle of 7xc2x0 or smaller.
[11] A molded or otherwise formed product comprising an organic polymer as defined in [8] or [9].
[12] Use, as an antifouling material, of an organic polymer as defined in [1], [2], [3], [9] or [10] or a molded or otherwise formed product as defined in [4] or [11].
[13] Use, as an anti-mist material, of an organic polymer as defined in [1], [2], [3], [9]or [10] or a molded or otherwise formed product as defined in [4] or [11].
[14] Use, as a dew preventing material, of an organic polymer as defined in [1], [2], [3], [9] or [10] or a molded or otherwise formed product as defined in [4] or [11].
[15] Use, as a water(liquid) absorbent material, of an organic polymer as defined in [1], [2], [3], [9] or [10] or a molded or otherwise formed product as defined in [4] or [11].
[16] Use, as an optical material, of an organic polymer as defined in [1], [2], [3], [9] or [10] or a molded or otherwise formed product as defined in [4] or [11].